1. Field of the Invention
The invention pertains to the field of surface glare reduction, and more particularly, to the reduction of glare from cathode ray tube or touchscreen radar displays.
2. Description of the Prior Art
The glare of from a phosphor surface display in a well lit area creates a poor contrast ratio thereby adversely affecting the visual detail observable on the display.
One method in the prior art for reducing glare is to position a reflectionless coating on the surface of the display. Such a coating, however, affects the image quality and, in many cases, does not justify the increased cost involved. Additionally, this approach is not feasible for the reduction of glare from a touchscreen display, whereon control functions for a system are display on the screen and activated by a touch of the finger. This coating significantly reduces the sensitivity of the touchscreen to the finger touch, thereby preventing a control activation by the touch of a finger. Further, fingerprints are highly visible on this coating, thus adversely effecting the detection of small targets or other small display entries.
Other methods of reducing glare in the prior art utilize a shield positioned over the display surface and tilting the display so that light reflected therefrom is incident to the inner surface of the shield. This inner surface has a nonreflection coating applied thereto so that light is not reflected therefrom. Two purposes are served by this shield, it shields the display surface from light that is incident thereto at angles within a broad angular range and absorbs reflections from the display surface of light that is not intercepted by the shield. A shield of this type is disclosed in U.S. Pat. No. 4,032,222. For many applications, the viewing area required dictates a shield that intercepts only a small portion of the incident light. In these situations the display surface must be tilted at an angle, to reflect light incident to the display surface to the inner surface of the shield, that provides an unacceptable image foreshortening to the viewer of the display.